Exploratory analysis of CD63 and CD203c expression in basophils from hazelnut sensitized and allergic individuals.
BACKGROUND: Sensitization to hazelnut (HN) is frequent and requires clarification to determine whether this sensitization is clinically relevant. The aim of this study was to investigate basophil activation profiles in HN-sensitized and allergic subjects. METHODS: Basophil activation was determined by flow cytometric analyses of CD63 and CD203c expression using several HN allergen concentrations. Depending on their clinical reaction pattern, an oral allergy symptom group (OAS, n = 20), a systemic reaction group (n = 12) and a sensitized group without clinical symptoms (n = 20) were identified. Additionally, 10 non-allergic and non-sensitized individuals served as controls. RESULTS: CD63 and CD203c expression differed between allergic (OAS and systemic group) and sensitized subjects. The HN concentration required to activate 30% of CD203c+ basophils [effective concentration (EC)30] was significantly higher in sensitized versus the allergic group (p = 0.0089). This was more pronounced when the basophil allergen threshold sensitivity (CD-sens) was calculated (CD63: p = 0.018; CD203c: p = 0.009). CONCLUSION: Our data indicate that the basophil activation test may provide information to better distinguish between sensitized and allergic subjects if several allergen concentrations are considered. CD203c expression displayed a better discrimination compared to CD63; therefore, its diagnostic value might be superior compared with CD63.
Streamlining the analytical workflow for multiplex MS/MS allergen detection in processed foods
Allergenic ingredients in pre-packaged foods are regulated by EU legislation mandating their inclusion on labels. In order to protect allergic consumers, sensitive analytical methods are required for detect allergen traces in different food products. As a follow-up to our previous investigations, an optimized, sensitive, label-free LC-MS/MS method for multiplex detection of five allergenic ingredients in a processed food matrix is proposed. A cookie base was chosen as a complex food matrix and home-made cookies incurred with whole egg, skimmed milk, soy flour, ground hazelnut and ground peanut were prepared at laboratory scale. In order to improve the analytical workflow both protein extraction and purification protocols were optimized and finally a sensitive streamlined SRM based analytical method for allergens detection in incurred cookies was devised. The effect of baking on the detection of selected markers was also investigated.
Advances in food allergy in 2015.
This review highlights research advances in food allergy that were published in the Journal in 2015. The world of food allergy research continues to rapidly accelerate, with increasing numbers of outstanding submissions to the Journal. In 2015, important studies on the epidemiology of food allergy were published, suggesting differential rates of food allergy in specific racial and ethnic groups. Even more importantly, studies were published identifying specific risk factors for the development of peanut allergy, as well as specific prevention strategies. We also saw new studies on the diagnosis of food allergy and potential approaches to the treatment of food allergy, as well as novel mechanistic studies helping to explain the immunologic correlates of food allergy and food desensitization.
Identification and Characterization of Ana o 3 Modifications on Arginine Residue-111 in Heated Cashew Nuts.
Raw and roasted cashew nut extracts were evaluated for protein modifications by mass-spectrometry. Independent modifications on the Arg-111 residue of Ana o 3 were observed in roasted but not raw cashew nuts. The mass changes of 72.0064 or 53.9529 Da are consistent with formation of carboxyethyl and hydroimidazolone modifications at the Arg-111 residue. These same modifications were observed in Ana o 3 purified from roasted but not raw cashew nuts, albeit at a relatively low occurrence. Circular dichroism indicated that Ana o 3 purified from raw and roasted cashew nuts had similar secondary structure, and dynamic light scattering analysis indicated there was no observable difference in particle size. The stability of Ana o 3 purified from raw and roasted cashew nuts to trypsin was similar in the absence of or following treatment with a reducing agent. Only minor differences in IgE binding to Ana o 3 were observed by ELISA among a cohort of cashew allergic patient sera.
No difference in health-related quality of life, after a food challenge with cashew nut in children participating in a clinical trial.
BACKGROUND: Previous studies showed that Health-Related Quality of Life (HRQL) significantly improved after the food challenge, with greater improvements in HRQL after a negative outcome than a positive outcome. It is currently unknown whether this also occurs in patients undergoing DBPCFCs with cashew nut in the context of a clinical trial. METHODS: Quality of life was studied in children enrolled in a cashew nut study using food allergy quality of life questionnaires (FAQLQs). Children, teenagers and parents of the children completed the questionnaires before the challenge test and 6 months after the DBPCFC with cashew nut. The difference in the change in HRQL between the children with a positive and negative DBPCFC outcome was studied by Mann-Whitney U test. RESULTS: In total 112 children (67 boys, median age 9 yrs.) were included. The children, teenagers and parents of the children completed in total 143 sets of questionnaires. There were no significant differences in baseline total and domain scores compared to the follow-up scores in the FAQLQ-CF, -TF and -PF. In children, the delta FAIM score in the negative DBPCFC tested group was significantly better than the delta FAIM score in the positive challenged group (p= 0.026). There were no significant differences in the changes in the scores of the FAQLQ-CF and FAQLQ-PF in the children with a positive challenge outcome, compared to the children with a negative challenge result. However, there was a significant difference in the change in score between the latter groups in the domain 'accidental exposure' of the FAQLQ-TF (p=0.049). CONCLUSION: This study showed no difference in change of HRQL scores after a DBPCFC with cashew nut in children participating in a clinical trial. The utility of HRQL as an outcome for clinical trials in food allergy may be limited if participant baseline HRQL is relatively unimpaired. This article is protected by copyright.
Association of tree nut and coconut sensitization.
BACKGROUND: Coconut (Cocos nucifera), despite being a drupe, was added to the US Food and Drug Administration list of tree nuts in 2006, causing potential confusion regarding the prevalence of coconut allergy among tree nut allergic patients. OBJECTIVE: To determine whether sensitization to tree nuts is associated with increased odds of coconut sensitization. METHODS: A single-center retrospective analysis of serum specific IgE levels to coconut, tree nuts (almond, Brazil nut, cashew, chestnut, hazelnut, macadamia, pecan, pistachio, and walnut), and controls (milk and peanut) was performed using deidentified data from January 2000 to August 2012. Spearman correlation (ρ) between coconut and each tree nut was determined, followed by hierarchical clustering. Sensitization was defined as a nut specific IgE level of 0.35 kU/L or higher. Unadjusted and adjusted associations between coconut and tree nut sensitization were tested by logistic regression. RESULTS: Of 298 coconut IgE values, 90 (30%) were considered positive results, with a mean (SD) of 1.70 (8.28) kU/L. Macadamia had the strongest correlation (ρ = 0.77), whereas most other tree nuts had significant (P < .05) but low correlation (ρ < 0.5) with coconut. The adjusted odds ratio between coconut and macadamia was 7.39 (95% confidence interval, 2.60-21.02; P < .001) and 5.32 (95% confidence interval, 2.18-12.95; P < .001) between coconut and almond, with other nuts not being statistically significant. CONCLUSION: Our findings suggest that although sensitization to most tree nuts appears to correlate with coconut, this is largely explained by sensitization to almond and macadamia. This finding has not previously been reported in the literature. Further study correlating these results with clinical symptoms is planned.
Advances in ultra-high performance liquid chromatography coupled to tandem mass spectrometry for sensitive detection of several food allergens in complex and processed foodstuffs.
Sensitive detection of food allergens is affected by food processing and foodstuff complexity. It is therefore a challenge to detect cross-contamination in food production that could endanger an allergic customer's life. Here we used ultra-high performance liquid chromatography coupled to tandem mass spectrometry for simultaneous detection of traces of milk (casein, whey protein), egg (yolk, white), soybean, and peanut allergens in different complex and/or heat-processed foodstuffs. The method is based on a single protocol (extraction, trypsin digestion, and purification) applicable to the different tested foodstuffs: chocolate, ice cream, tomato sauce, and processed cookies. The determined limits of quantitation, expressed in total milk, egg, peanut, or soy proteins (and not soluble proteins) per kilogram of food, are: 0.5mg/kg for milk (detection of caseins), 5mg/kg for milk (detection of whey), 2.5mg/kg for peanut, 5mg/kg for soy, 3.4mg/kg for egg (detection of egg white), and 30.8mg/kg for egg (detection of egg yolk). The main advantage is the ability of the method to detect four major food allergens simultaneously in processed and complex matrices with very high sensitivity and specificity.
Experimental food allergy to peanut enhances the immune response to house dust mite in the airways of mice.
BACKGROUND: Food allergy has been associated with an increased risk for the development of allergic asthma. Asthma is a risk factor for the development of an anaphylactic response to food allergens. An immunological interplay between sensitization to different allergens in different compartments of the body might be involved. OBJECTIVE: To evaluate the immunological interplay between intragastrical peanut (PE) sensitization and respiratory sensitization to house dust mite (HDM) allergens. METHODS: BALB/c mice were intra-gastrically sensitized to peanut or sham-sensitized and challenged systemically to PE. Between sensitization and challenge, mice were intranasally exposed to HDM extract or PBS, as a control. The response to HDM (eosinophil recruitment, cytokine response, HDM specific immunoglobulins, and airway hyperreactivity) and to PE (cytokine response, mast cells in gut, mMCP-1 in serum, body temperature) was assessed. RESULTS: A preceding PE sensitization increased HDM induced production of IL-4, IL-5, IL-13 and IFNγ in lung draining lymph nodes and total IgE levels in HDM sensitized mice. However, recruitment of inflammatory cells to the airways or airway hyperreactivity was not aggravated in PE/HDM double-sensitized mice. Alternatively, HDM induced airway inflammation did not significantly affect the immune response or the anaphylactic response to a systemic challenge with peanut. CONCLUSION AND CLINICAL RELEVANCE: Our data show that a preceding peanut sensitization boosted IgE and HDM-specific Th2 response in the airways in mice. It contributes to the understanding of the underlying immunological mechanism of polysensitization which often occurs in allergic individuals over time.
Three peanut allergic/sensitized phenotypes with gender difference.
BACKGROUND: Peanut allergic reactions are heterogeneous ranging from mild symptoms to anaphylaxis. OBJECTIVE: Identify peanut allergic/sensitized phenotypes to personalize patient management. METHODS: A combined factor and cluster analysis was used to study the phenotypes of 696 patients diagnosed with peanut sensitization and enrolled in the MIRABEL survey. The method was first applied to the 247 patients with an Oral Food Challenge (OFC). It was then applied to the 449 patients without OFC to confirm the findings in an independent population. RESULTS: Three independent clusters emerged from the OFC subgroup. Cluster 1, "Severe peanut allergy with little allergic multimorbidity" (123 subjects), had the highest proportion of patients with positive OFC (92%), a medium level of peanut protein inducing a positive OFC (235 mg), lower percentage of allergic multimorbidity (2% asthma plus atopic dermatitis (A+AD), no cases of A+AD + multiple food allergies (MFA)). Cluster 2, "Severe peanut allergy with frequent allergic multimorbidity" (62 subjects), had a high proportion of patients with positive OFC (85%) with the lowest level of peanut protein inducing a positive OFC (112mg), 89% allergic subjects, 100% with allergic multimorbidity (A+AD) and 84% with A+AD+MFA. Cluster 3, "Mild peanut allergic/sensitized phenotype" (62 subjects), had the lowest mean age, the lowest proportion of patients with positive OFC (53%) with a high level of peanut protein inducing a positive OFC (770 mg), a low percentage of allergic multimorbidity (48% A+AD+MFA). The two severe peanut allergy phenotypes were more frequent in girls. The same clusters were found in the subgroup of patients without OFC. CONCLUSION & CLINICAL RELEVANCE: Besides the classic markers associated with lower threshold doses of OFC (such as SPT and rAra h2), allergic multimorbidity and female gender should also be taken into account to better adapt the progressive dosage of provocation tests.
Food allergy in children.
Food allergy represents a highly up-to-date and continually increasing problem of modern man. Although being present in all ages, it most often occures in children aged up to three years. Sensitization most often occurs by a direct way, but it is also possible to be caused by mother's milk, and even transplacentally. Predisposition of inadequate immune response to antigen stimulation, reaginic or nonreaginic, is of non-selective character so that food allergy is often multiple and to a high rate associated with inhalation and/or contact hypersensitivity. Also, due to antigen closeness of some kinds of food, cross-reactive allergic reaction is also frequent, as is the case with peanuts, legumes and tree nuts or cow's, sheep's and goat's milk. Most frequent nutritive allergens responsible for over 90% of adverse reactions of this type are proteins of cow's milk, eggs, peanuts, tree nuts, wheat, soy, fish, shellfish, crustaceans, and cephalopods. Allergy intolerance of food antigens is characterized by a very wide spectrum of clinical manifestations. Highly severe systemic reactions, sometimes fatal, are also possible.The diagnosis of food allergy is based on a detailed personal and family medical history, complete clinical examination, and corresponding laboratory and other examinations adapted to the type of hypersensitivity and the character of patient's complaints, and therapy on the elimination diet. A positive effect of elimination diet also significantly contributes to the diagnosis. Although most children "outgrow" their allergies, allergy to peanuts, tree nuts, fish, shellfish, crustaceans, and cephalopods are generally life-long allergies.